1. Field of the Invention
This invention relates to an elastomer to which special attention has recently been paid, and more particularly this invention relates to a novel lactone-modified diol which can be used as a soft segment component which provides a thermoplastic elastomer showing excellent performances in elastic recovery and low-temperature properties.
2. Description of the Prior Art
Conventionally known thermoplastic elastomers include those of polyesters, polyamides and segmented polyurethanes, and these elastomers generally contain polyalkylene ether diol, for example, polyethylene glycol, poly(1,2- or 1,3-propylene) glycol, polytetramethylene glycol, polyhexamethylene glycol, ethylene oxide/propylene oxide block or random copolymers and ethylene oxide/tetrahydrofuran block or random copolymers. Of these, polytetramethylene glycol is generally used from the viewpoint of, especially, heat resistance, water resistance, mechanical strength, elastic recovery and the like, but when use is made of a block copolymer having a so-called micro-phase separation structure, that is, a distinct micro-domain structure, formed by slightly lengthening a soft segment chain in order for the copolymer to exhibit the function as a soft segment fully, the properties such as low-temperature properties and elastic recovery are not necessarily satisfied in the present situation, because of the tendency of polytetramethylene glycol toward crystallization.
Concerning, for example, a segmented polyurethane elastomer, Japanese Patent Laid-Open No. 160016/1980 proposes a process comprising using a lactone-modified polyether diol prepared by adding polycaprolactone to polytetramethylene glycol as one for improving the heat resistance, mechanical properties, hydrolysis resistance, and low-temperature resistance of the copolymer. However, this process is not yet satisfactory in respect of, especially, elastic recovery.